B3 - Discontinuity of the Vertical Elements of the Structural System: The situation where the vertical elements of the carrier system (columns or curtains) are lifted on some floors and placed on the top or end of the beams or gusset columns, or the curtains on the upper floor are placed on the lower columns ( Figure 3.4 ). - Conditions for buildings with irregularities of type B3 are specified in (a) to (d) below :

(a) It is never permitted to sit the columns on the top or the end of the cantilever beams or gusses formed in the columns below on any floor of the building.

(b) If the column rests on a beam with support from both ends , a vertical earthquake calculation according to 4.4.3 is sufficient.

(c) The curtain on the upper floors is never allowed to rest on the columns below.

(d) It is never permitted to sit curtains on any floor of the building, in their own plane, above the beams in the middle of the opening.